Smart cards are standardized articles described in particular in ISO standard 7816 and their main function is to enable electronic transactions to be performed by identifying the bearer. To this end, smart cards include a chip whose circuits integrated on a silicon substrate define various functional elements, and in particular a central processor unit (CPU) and volatile memory (RAM), non-volatile memory (ROM) and electrically erasable and programmable non-volatile memory (EEPROM). The central processor unit (CPU) manages data and addresses in the various memories by means of a bus. In general, data and addresses are respectively encoded on 8 bits and on 16 bits.
The integrated circuit chips are provided with six contact pads: these pads being identified by the initials VCC, GND, VPP, RST, CLK, and I/O, and serving respectively to supply the chip with electricity, to ground it, to supply it with a programming voltage, to reset it, to input a clock signal, and to perform data input and output. These pads are electrically connected to contact areas that are flush with the surface of the card. The VCC pad is connected to an area C1, the GND pad to an area C5, the VPP pad to an area C6, the RST pad to an area C2, the CLK pad to an area C3, and the I/O pad to an area C7.
Part 2 of above-specified ISO standard 7816 relates to the number, size, and positioning of the electric contact areas on the card. Thus, as defined in that standard, in addition to the areas C1, C5, C6, C2, C3, and C7, the card also has two areas C4 and C8 that are reserved for future use. No function has been allocated to these areas which are not connected.
Part 3 of the 7816 standard relates to the various transmission protocols and signals that the card must comply with. In the protocols known as T=0 and T=1, data is transmitted solely via the I/O pad in half-duplex mode and asynchronously, using defined formats. The data rates authorized in those data formats and protocols are slow, of the order of 38 kilobits per second (kb/s) and multipoint links are not allowed.
As a result, when a state of the art card is to be used with a non-specialist terminal which does not make use of the above-specified protocols and formats of Part 3 of the 7816 standard, i.e. in fact most terminals available on the market, and in particular personal computers, it is necessary to use a card reader which serves not only to turn the card on and off, but also to perform protocol conversion and to reformat data so as to make it usable by the card. Since the data rates allowed for the card are slow, it cannot be used for applications that require fast transfer of data such as encoding/decoding information in real time.